How Do You Bake With The Wilton 3D Bear Pan Without Losing All The Batter?

AI just got the Wilton 3d standup bear pan and am wondering how, following their instructions, you are supposed to bake the cake on its side without losing half the batter as it runs out? Also, if you use the heating core, there seems to be no way of keeping it in place unless you bend the tabs. Is that correct? Fortunately the oven I'm using right now is tall enoug to bake the cake standing up, but that won't always be the case. Thanks for any advice!